Home > Solar and Space Plasma (SSP) Seminar | 国立天文台談話会 | 科学研究部コロキウム > 2021.3.22-2021.3.28

2021.3.22-2021.3.28

3月24日(水)13:30~15:00   NAOJ Science Colloquium               zoom
Mar 24 Wed  

3月26日(金)13:30~15:00   Solar and Space Plasma Seminar            zoom
Mar 26 Fri          

3月26日(金)16:00~17:00   談話会                        zoom
Mar 26 Fri           NAOJ Seminar

詳細は以下をご覧下さい。

3月24日(水)

Campus
Mitaka
Seminar
NAOJ Science Colloquium
Regularly Scheduled/Sporadic
Every Wednesday

Date
2021 March 24
Time
13:30-15:00
Place
Zoom
Speaker
Hu Bochao (Tokyo Tech., Student talk in Japanese)
Title
Calculations for radio and infrared observations of circumplanetary disks:Conditions for satellites formation
Abstract
Satellites are believed to be formed from circumplanetary disks. There are various theoretical models of satellite formation, but there are few observational constraints on the physical quantity of the circumplanetary disks. It is known that the ice-rock ratio of Jupiter’s moons are not uniform. In the hot regions inside the water snow line in the circumplanetary disks, ice vaporizes and rocks become the main material for satellites. Therefore, it is important to investigate the physical quantity of the circumplanetary disks, especially the temperature, when considering the conditions for satellite formation. In recent years, detailed structures of protoplanetary disks around many young stars have been observed using high-resolution ALMA telescopes. In addition, structures similar to the circumplanetary disks were discovered. It is also expected that the infrared space telescope JWST, which is scheduled to be launched in 2021, will detect more circumplanetary disks.
In this study, we aim to establish a method for investigating the temperature of the circumplanetary disks by comparing model calculations with these observations. Previous studies have predicted the intensities of the dust and gas emission at (sub)millimeter wavelengths of the turbulent viscous accretion disks (Zhu et al. 2018) and the irradiation heating disks (Rab et al. 2019), for ALMA observations. In this study, we perform model calculations of dust and gas emission from circumplanetary disks, using the viscous accretion disk model, for JWST and ngVLA observations, and investigate how the intensities change for the models with different physical quantities, such as the accretion rate and the viscous parameter, alpha. As a result, it was shown that the circumplanetary disks is detectable relatively easily with dust continuum emission by JWST. Furthermore, chemical reaction calculations were performed to predict the intensities of various molecular lines and investigate how the infrared and (sub)millimeter line intensities depend on the physical quantity of the disk, and their detectabilities were also investigated. It is possible to constrain the physical properties of dust from radio multi-wavelength observation. It was suggested that the detection of dust emission by high-sensitivity observations of ngVLA may constrain the conditions for satellites formation.
Facilitator
-Name:Akimasa Kataoka

3月26日(金)

Campus
Mitaka
Seminar
Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic
Sporadic
Date and time
26 March (Fri), 13:30-15:00
Place
zoom
Speaker
Yoshiki Hatta
Affiliation
NAOJ
Title
Dynamics and structure around the convective core boundary of KIC 11145123 probed by asteroseismology
Abstract
There is often a close relation between stellar internal dynamics and structure. Solar tachocline, which is located around the base of the convective envelope in the Sun and defined as a region where a relatively strong rotational velocity shear develops, is one of such examples. In this talk, we would like to present asteroseismic analyses of internal dynamics and structure of KIC 11145123, one of the Kepler targets thought to be sightly more massive than the Sun (~1.4 solar mass) and have the convective core and the radiative envelope. First, we focus on the gravity-mode period spacing pattern observed for the star, based on which it has been indicated that the chemical composition gradient in the deep radiative region of the star might be much steeper than that of the model constructed via a 1-dimensional stellar evolutionary code. Then, the rotational velocity of the star has been asteroseismically inferred. In particular, we discuss a detection of the fast-convective-core rotation in detail. Finally, a possible relation between the inferred chemical composition gradient and fast-convective-core rotation is discussed. Though exact mechanisms to render the chemical composition gradient so steep have been not fully clear yet, this is the first study which tests the possibility that there is a relationship between the current rotational profile and the structure of stars other than the Sun, and to investigate such relationship should be one of the most highly prioritized subjects to future researches.
Facilitator
-Name:Munehito Shoda

3月26日(金)

Campus
Mitaka
Seminar
NAOJセミナー
Regularly Scheduled/Sporadic
Regular
Date and time
26 March (Fri), 16:00-17:00
Place
zoom
Speaker
梶野 敏貴 / Kajino, Toshitaka
Affiliation
国立天文台 科学研究部 / Division of Science,NAOJ
Title
神秘の宇宙・元素・生命の誕生 Mysterious link among the birth of the universe, elements and life
Abstract
真理の探究に終わりはなく、基礎科学はボーダーレスに発展しています。
天文・物理・生命など異分野がクロスオーバーし、「宇宙のはじまりと進化ー
元素の起源ー生命の誕生」という大きな謎の連鎖が解かれようとしています。
私は宇宙核物理学という新分野を拓き、この謎の解明に取り組んできました。
今後、自然科学はどのように発展していくのでしょうか。
日本の科学技術力が世界の最先端に躍り出た時代に生きる一人として、
翳りを見せ始めた日本の輝きを取り戻すために何が求められているのか、
また最終的に国益をもたらす国際研究協力の重要性にも触れたいと思います。
The quest for truth is endless and the developing basic science is borderless.
Crossing over different fields such as astronomy, physics and life science, the biggest and mysterious chain of
“the beginning and evolution of the universe – the origin of elements – the birth of life” is being solved.
I have ever tried to elucidate this mysterious link by opening and establishing a new pioneer field of Cosmo-Nuclear Physics.
How will the basic science develop in the future? The progress in science and technology of Japan has begun to fade in recent years.
As one of the scientists living in an era when Japan has jumped to the forefront of the world science,
I will discuss what is required to regain brilliance. I would also like to discuss the importance of global international
research cooperation that should ultimately bring national interests to Japan.
Facilitator
-Name:青木 和光 / Aoki, Wako

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